The present invention relates to a method of fabricating flash memory devices. More particularly, the present invention relates to a method of fabricating flash memory devices in which the interference between adjacent cells can be prevented.
As flash memory devices get smaller, the distance between cells is narrowed and coupling capacitance between cells is increased.
An increase in such coupling capacitance means an increase in the interference between adjacent cells. It means that a threshold voltage after programming and erasing a specific cell is varied according to the operation of adjacent cells.
Such interference causes an increase in the distribution of a threshold voltage. It also generates error in the cell operation, such as program disturb, pass disturb and read disturb.
An increase in the distribution of the threshold voltage due to the interference makes it difficult to fabricate a Multi-Level Cell (MLC) requiring a small threshold voltage distribution in comparison with a Single Level Cell (SLC).